Low water alarm



Aug. 16, 193;.

F. M. ROBY LOW WATER ALARM Filed Oct. 21 1927 :s Sheets-Sheet 1 gmmtoz attomew :Aug. 16, 1932. F. .M. ROBY 7 LOW WATER ALARM Filed Oct. 21. 1927 a Sheets-Sheet 2 atkomwzqq Patented Aug. 16, 1932 STATES FRANK M. ROIBY, or oLEvELAnn, omo

. LOW WATER ALARM Application filed. October 21, 1927. Serial No..2 27,760.

This invention relates to a low water alarm for steam boilers, but is shown particularly in this application locomotive boilers.

as designed for use with A satisfactory low water 5 alarm for locomotive boilers is illustrated in the patent of Herman B. Thurston No.

1,684,897, issued September 18-, 1928. Briefly, such alarm embodies a reservoir which is mounted outside the boiler and above the normal water level thereof.

valve is mounted within t adapted A float actuated he reservoir and is to control the operation of an alarm when the water level in the boiler drops to a pro-determined point. a fill pipe WlllCll communi er below the normal water Such reservoir has cates with the boillevel thereof, and

the area of an opening into the fill pipe is so arranged that thereis a predetermined interval of time between the uncovering of the bottom of the fill pipe and the sounding of the alarm.

alarm when the water surges This prevents operation of the toward the forward end of the boiler, and thereby reduces the depth over the crown sheet for a short interval of time.

In the operation of such alarm, it has been found that the evaporation of any water passing through the opening of the whistle valve, or any sli ht leakage of water past the valve seat caused a deposit that in time would prevent the passage of sufiicient steam to properly sound the alarm whistle. Moreover, any

material which may be in solution,

or which may be left as a deposit'tended to accumulate upon the valve seat and valve open.

to hold the alarm An object of the present invention is to make certain improvements or refinements of construction in the alarm illustrated in the 4 Thurston application,

so as to permit proper the so called bad water districts when treated water is customarily used.

protect the operating parts from damage either while the alarm is in operation, or

while the operating parts the reservolr casing.

are removed from The preferred construction of alarm emplane indicated by the line bodying my invention is illustrated "in the drawings, wherein Fig. 1 is a cross sectional diagram of a locomotive boiler showing the usual position in which this type of alarm is mounted on the boiler; Fig. 2 is a plan view of the alarm apart from the boi1er; Fig. 3 is an end view of the alarm onan enlarged scale; Fig. 4: is a vertical transverse section through the alarm; Fig. 5 is a vertical longitudinal section through the alarm and is taken'more particularly on a plane indicated by the line 55 in Fig. 4; Fig. 6 is a horizontal view taken on a plane indicated by the line 6-6 in Fig. 5; Fig. 7 is an enlarged detailed sectional View of the alarm adjacent the valve chamber; Fig. 8 is a vertical transverse section taken through the alarm on a 8-8 in Fig. 7 Fig. 9 is a horizontal section through part of the float rod guide, more particularly is a section taken on a plane indicatedin the line 99 in Fig. l; and Fig. 10 is an enlarged detailed vertical section through the device adjacent the valve chamber showing a modified form of connection between the valve be connected to the interior of the boiler by a fill-pipe 14, the lower end of whichterminates below the normal water level of the boiler. The top of the fill-pipe is indicated at 15 as terminating adjacent the top of the reservoir, and more particularly directly beneath and in line with a removable plug'16 in a closure plate 17. The purpose of such plug is to permit the interior of the fill-pipe to be cleaned from a point outside the boiler. In the preferred form, such fill-pipe comprises two sections, the upper of which is indicated at 18 as being connected to the reservoir at 19, and the lower of which, heretothe. main reservoir and. .by. providing 7 fdrainage .back of. the. boiler from.v the valve wardlyi from-the. .platewa-nd fore indicated at 14, is attached to the reservoir at 20. Between the points 19 and 20 there is formed a chamber 21 in the casing, and such chamber is arranged to be in communication with the .niain reservoir through an opening 22. The area of such opening controls the rate at which water may leave the reservoir andflow :back into, the boiler.

The rise and fall of water in the reservoir is utilized for controlling the rise and fall of a float 25, which in turnsoperates:ithesalanm valve. In the present embodiment, such valve is indicated in Fig. 7 as a head memberQG-and a seat member 27. The head and seat members are mounted in a valve chamber'28 which .is separated fromthezmain reservoir.

' maintaining. the valve chamber apart i-rmn proper chamber for fthewwaterentering from..the

vmain reservoi-r around: the reduced section 20f. the. valve stem there would be no opportunity for water to accumulate, in the valve chamber, :and thereby to form. deposit ,on

.the valve seat, or subsequently inthe passage- :waynto the. alarm whistle, which may. interiere with the properoperation of the valveor Alarm whistle.

The-valve head is'connecte'd toathe float in such manner that vertical .movement of thelfioat will effect rectilinearmovement-of .the head. i Asimpleway of .mal singsuch connection .is to so make the float rod .24 that it terminates in; a yoke adj acent. the valve .end

thereof. ';The lowerrend .of. the yoke [portion ishthen pivotallymounted, .as at 30,to: the plate 31 whichformszair-end .closurefor the reservoir. The iupperend, of the'yoke isip-ivot- .afllvconnected, .as:at.39,' to the valve stem 32.

f A yoke, shaped "keeper 33then extendsfdown- .wardlyalong the outer sides of the yoke portitms-andkeeps the :pi-ns from falling out of plecemndat the same time obviates the necessityfoncotter pinszand. the like,-which other- Wise would be required for holding such pins in: place.

As heretofore explained,cthe valve, rod and stem assembly His mounted .-;on the; plate 31 which is-:fast-ened by suitable securing: members-35 to. the end of the reservoir. .Inorder therefore 1 to ,protect the .va-lve stem in. the eventsuch plate :is removed from thecas-ing; I haveshovmna projection 36 which extends inserves to engage theundersurfaceof the float rod-24, and;:preyent-excessive'outward movement of the valve stem with reference: to the plate, so. that the stem :ca-nnotrbind; in the split bushingx57 or :become bent.

. iTogprevent the sides of the float. from engaging .thercasing while moving therein, I employ: a guide :member; 40 which preferably extends downwardly from. the closureplate casing. i'lihe lewerwendrof such member. is

bifurcated, as at 41, and such bifurcated portions function as lateral guides for the float rod 24. To minimize friction such guides are shaped to make a thin edge 42 (Fig. 9) along that portion which may be in contact with the rod.

To prevent the accumulation of sediment at 'theiibottom of, the casing from forming a suction which may tend to hold the float in "lowered position, I provide an abutment 45 aatzthe=bottomofthe casing. The top of such abutment is above the bottom of the blowout :openin-g lti. This provides a support for the float and enables it to be operated in a satisfactorymanner, notwithstanding the usual ,accumulation of sediment.

In practice, the valve chamber being sub- ,ijected-tolhigh pressure steam, and the float .chamber being :subjected to the same pres- .sure, it would appear that the pressurein the valveandf float chambers would be equal. However asaimatterof fact, the large float chamber offers moresurface'for condensation of steamtherein, and hence there is a slightly ,lowernpressurelin the float chamber than in [the valveschamber. .Asa result, there is a .tendencyfor steanito flow from the valve chamber into. thedloat' chamber faster. than .the float chamber: would be able to condense itand: thus interfere with. the float chamber completely filling with W2Lt61,flt it should do for. the. normal operation of the alarm.

Jnhave foundv that if the valve stem is substantially the same diameter as the valve fh-ead,'iand if. even only a. few thousandths of ,aninch, clearance is. permitted between the stem and the, bushing, that .such clearance area. willaallow suflicient steam to flow from .con'duit 151 through thevalve chamber and back into the float chamber ,to prevent the water .fromrising .toithe top of the float chamber. 'I prevent the passage of steam in such. quantities by utilizing .a shank having a reduceddiameterfrom thatof the head, and by utilizing a-s-plit bushing 57 which is shown as being threaded into the plate 31. and as .havinganopening 8, Figs. 7,11 and 12, which is onlylarge-enough to permit the shank to havea tight-slit g-fittherein. Any irregular-itiesin alignmentare compensated for by enlarging the opening in the pivotal-end 7 of the;shank,.-such+end being held in place by the; pivot pin '39. In this way excess steam cannot -flow fronrthe valve chamber into the float chamberand interfere with the proper'iillingof the float chamber with water.

In the normal operation ofa 'device of this character, assuming that the boiler is filled to its.normallevelwith water,'as the steam 'pressurerises the water will be forced upwandly through the fill-pipe and into the reservoir. As the float rises with thewater it shuts-off the: alarm valve and maintains it shut so long as the water-remains at a predelie termined level i-ni the reservoir. .If the water and prevents passage of any falls below the? lower "end of the fillPipe 1 1,

' size of the opening and the water in the reservoir. will gradually fall tot-he .point where the float opens the. alarm valve by withdrawing the valve stem 26. As soon assuch' valve is opened then-steam will flow into the alarm conduit and thus sound the alarm whistle 54a.v Normally, the valve chamber is subjected to steam pressure at all times by reason of the fact that a conduit 51 is directly connected to the steam space in the boiler at connection 52. Such conduit functions in a satisfactory manner to drain the valve chamber.

For purposes of testing the alarm at any time, without having to lower the water in the boiler, steam may be introduced into the upper portion of the reservoir thru the pipe 55 shown particularly in Fig. 5 under the control of a hand valve 56. The pipe 555 communicates with the steam portion of the boiler or with a steam line and the valve 56 is closed except for test purposes. On opening the valve the steam entering the top of the reservoir will release the hydrostatic head and permit the water to flow through the 7 opening 22 until the float actnates the valve stem 26, thus opening the valve and causing the alarm to be sounded. Upon closing the hand valve 56 the reservoir again fills with water as previously described, thus raising the float and closing the alarm valve. The

escape of the water from trie reservoir and the operation of the alarm is exactly the same, when using the test valve, as when due to a low water condition in the boiler.

In Fig. 10 I have shown a modified construction for connecting the valve stem to the float rod. Such construction, instead of employing an opening in split bushing 57, as. shown in Fig. 7, comprises a diaphragm 60 which is attached respectively to the valve stem 26a and to the end plate 31a. This diaphragm then seals ofl' the connection between the float chamber and the valve chamber water from the float to the valve chamber. This insures a clean valve seat and steam outlet to whistle at all times, since the valve is subjected only to dry steam.

A low water alarm made in accordance with my invention is advantageous in that it maintains the valve constantly in an atmosphere of dry, live steam and thus prevents any deposit on the valve seat which might interfere with the proper seating of the valve. 1 accomplish this result without danger of the live steam leaking along the valve stem into the float chamber and interfering with the proper functioning of the latter. Moreover the mechanical improvements set forth herein serve to assure proper operation of the float and valve as well as to protect the valve when the assembly is removed from the cas- 111 a T claim:

1. A device of the character described, com

rising a reservoir, an alarm indicating memer, a valve for controlling said member, a stem associated with said valve and a float in the reservoir for operating the, valve, .a connection between the float and valve comprising a pivoted float lever having an arm portion extending transversely to the valve stem, a. removable pin connecting the armand valve stem and a U-shaped keeper removably mounted on the float lever and overhanging-the opposite ends of the pin to retain: the same, in place.

2.. In a device of the character described, the combination with a reservoir casing, of a float arranged to be moved vertically therein,'a float ar m, said arm. being forked at the end opposite the float and being pivotal-.

ly connected to one wall of the casing, a valvestem extending through said wall and betweenthe forked portions of said arm, a pivot pin extending through the forked portions and the valve stem, and a yoke removably connectedto the arm and engaging the outer ends of. said pivotal connectionsfor holding the same in place.

3. In a device of. the character described, the combination of a reservoir, a fioatvoperable therein, a valve forcontrolling a conduit to an alarm indicating device, an arm for the float connected with the valve,-and stationary means carried by the casing and standing vertically on opposite sides of the float arm and servingto-guide it, said stationary means being formed to present sub stantially line edges on opposite sides of the float arm. V I

4.. In a. device of the character described, the. combination of a reservoir, 21, valve, a float within the reservoir, a lever pivoted to the stationary part ofthe reservoir connecting its free end with the float and having anarm connected With the valve and a narrow abutment carried by the bottom wall of the casing projecting upwardly therefrom and adapted to engage the float in its lowermost position and maintain it distant from the bottom of the reservoir for substantially the whole surface of the float.

5. In a device of'the character described, the combination with a reservoir casing having one end thereof open, a detachable closure plate therefor, said plate having a Valve chamber leading outwardly therefrom, a valve in said chamber, a float pivotally mounted on the reservoir side of the plate, a'valve stem extending. through the plate and being operatively connected to the float, and means carried by said plate on the reser- VOI l1;Sl(l6 thereof for limiting movement of r so.

the float in adownward'direction when the pl ate'is detached from the casing. V

6. In a device of the character described, the combination with a boiler, of a reservoir mounted thereon and at a higherilevel than the normal low water level of the boiler, a hollow sealed floatwithin said reservoir but having no portion. of the same at a higher level than the top of said reservoir, a valve chamber separate from the reservoir and having a valve seat therein, and spaced the valve chamber and arranged to be actuated by said; stem, said stemv being arranged :to be actuated by the float consequent upon the risexandgfall of water in :thereservoir for controlling the operation of the indicating-member, and independent means connecting the valve chamber to a source of steamisupply.

Initestimonywhereof, I hereunto affix my signature;

. FRANK fNL ROBY.

from the wall of the chamber, whereby the ed. at one end thereof to the float and pivotal- 1y connected at the other end thereof to the wall of the reservoir, said arm being also pivotallyconnected to the valve stem, whereby the movement ofarm in a vertical plane and'in a plane of the valve stem transmits a substantially horizontal movement to the valve stem, a-conduit leading from the reservoir into the boiler and terminating below the normallow water level of the boiler, and another conduit leading from the valve chamher and terminating within the boiler above the normal water level thereof, said last named conduit functioning to drain the valve chamber and to supply steam thereto, an alarm indicating member connected to the valve chamber said member being adapted to be actuated by steam from said chamber when the valve is opened, and said valve being adapted to be controlledv by the rise and fall of water within the reservoir and in.- dependently of the pressure within the reservoir.

7. The combination with a boiler, of a reservoir disposed above the normal water level of the boiler, a hollow sealed float with in said reservoir, a conduit leading fromthe reservoir to the interior of the boiler and terminating below the normal water level thereof, an alarm indicating member, a valve chamber associated with said alarm indicating member and located adjacent to but separatefroin the reservoir, said chamber being arranged to communicate with said member, a wall separating the reservoir from the valve chamber, a split member in said wall and provided with an aperture therethrough, a valve stem provided with a reduced intermediate portion arranged to pass through the aperture in said split member whereby a tight sliding fit between the stem and said split member is provided, a valve mounted 

